How will I know he likes oral sex?

When I go down on a guy how will I know if he likes it or not because I went down on my friend and he didn't say anything after he just gave me a kiss and left

What did you expect him to say?...he was using you. What dont you see?! If you dont start respecting yourself, then no one is going to. Guys will only see you as a toy, not as a person. I have such a hard time with girls who give a guy what he wants because he asks, when they arent even in a relationship with him. This isnt going to make them like you if thats why you do it. They are only going to want you for one thing. You need to be in a long commited relationship before you do anything intimate with a guy! Otherwise, the only relationship you will continue having, is with a males anatomy.

thats kinda awkward.
and if a guy likes it then its easy to tell
if he just gave you a kiss & then left
thats not good. its like thats all he wanted